OF ARTS AND SCIENCES. 267 



inches in diameter. Lower tubercles 2-3, floriferous ones 5-6 lines 

 long ; spines 3-5, upper fasciculated ones 6-9 lines long. Flower 

 2| - 3 inches in diameter ; seed 0.9 line long. 



21. M. Echinus, E. 1. c. : simplex, globosa ; tuberculis tereti- 

 conicis ; areolis orbiculatis ; aculeis rectis s. pauUo curvatis intertextis 

 albidis ; radiantibus 16- 30 summis pauUo longioribus, centralibus 3- 

 4, inferiore robustissimo subulate porrecto, superioribus 2 - 3 et cum 

 radiantibus erectis ; floribus magnis. 



With the former. — Plant l2--2| inches in diameter; tubercles 

 5-6 lines long ; lower and lateral spines 4-6, upper ones 6-10 

 lines long ; upper central spines of the same length, and the lower 

 central one a little shorter. This last one is unusually stout, subulate 

 from a very thick base, and perpendicular on the centre of the plant, 

 which gives it a very peculiar aspect. Flowers apparently about 1^ 

 or 2 inches long. 



22. M. scoLYMoiDES, Scheidw. (1841): globosa s. ovata, subsim- 

 plex ; tuberculis conicis, supei'ioribus elongatis incurvis imbricatis ; 

 aculeis radiantibus 14-20 rectis s. plerumque recurvis albidis s. cor- 

 neis, superioribus longioribus, centralibus 1 - 4 longioribus obscuriori- 

 bus curvatis, superioribus sursum versis cum radialibus implicatis, 

 inferiore robustiore longiore decurvo. 



South of the Rio Grande ; not yet discovered in our territory. — 

 Plant 2-3 inches high ; tubercles 5-8 lines long; radial spines 5- 

 10 lines, the central ones 9-16 lines long. Flowers yellow, 2 inches 

 long. — Perhaps this and both the foregoing species are only forms of 

 the Mexican M. cornifera, of De Candolle. Only a close examination 

 of these plants in their native wilds will enable us to decide this point. 



23. M. CALCARATA, E. in PI. Lindh. 2, 1850 (M. sulcata, E. in 

 Pl.Lindh. 1, 1845. M. strobiliformis, Muhlenpf.? non Scheer) : glo- 

 bosa, prolifera, csespitosa ; tuberculis e basi dilatata ovatis conicis ; 

 aculeis albidis, radialibus 8-10 rigidis subulatis rectis s. pauUo re- 

 curvis, additis subinde ex summa areola aculeis adventitiis 3-5 fas- 

 ciculatis tenuioribus, centrali singulo robustiore subulate recurvato, in 

 plantis junioribus deficiente; floribus magnis sulphureis intus basi 

 rubicundis. 



Texas, from the Brazos to the Nueces rivers : fl. May. — Larger 

 heads 2-2^ inches in diameter ; csespitose masses a foot or more 

 large ; tubercles spreading, or in older flowering plants often some- 

 what adpressed and imbricate, 7-9 lines long; spines 4-8 lines 



